1. Field of the Invention
This invention relates to caps or plugs for temporarily sealing plumbing systems in structures for testing, and in particular to a plug for temporarily sealing a shower pan drain.
2. Description of the Related Art
Drainage systems are used in structures to carry away waste water, human wastes, ground garbage from disposers, and the like to municipal sewers or septic tanks. Drainage systems also serve as conduit for noxious gases which are vented to the atmosphere outside of the structure. A particularly necessary quality of such drainage systems is integrity of the pipes and joints such that the liquids or gases carried do not leak.
In order to ensure that a drainage system does not leak, pressure testing is often conducted and may be required by some local codes. Plumbing is preferably installed, tested, and joints repaired, as needed, prior to closing access to the piping and joints by the installation of wallboards. Pressure testing often involves pressurizing the drainage system with compressed air, or alternatively filling it with water, and detecting any leaks. Pressure testing is usually done before any fixtures, appliances, or the like have been connected to the drainage system.
Plastics, such as PVC (polyvinyl chloride), ABS (acrylonitrile butadiene styrene) and others, are used in many types of plumbing, including waste plumbing. It is common practice, during pressure testing, to install removable test plugs or caps on pipe stubs to which fixtures, such as toilets, will be subsequently connected. After pressure testing is completed, the caps are removed. The test caps need to be sealed in place such that they do not leak during testing. When the test caps are no longer needed, they need to be removed in such a manner that the test cap is not lost in the waste plumbing, such that the remaining plumbing is not damaged by removal of the test cap, and such that no remaining parts of the test cap assembly interfere with the fixture to be installed.
During testing of a drainage system, drains such as shower pan drains and floor drains also need to be sealed. Shower pan drains typically include a body that connects to the drainage system and a collar which is removably connected to the body by bolts or the like. A flexible membrane which seals the shower floor is clamped between the body and the collar. The finished shower floor is installed on top of the membrane. The collar includes a central threaded aperture which receives a drain head, including a strainer. The collar also includes numerous smaller openings which are intended to direct any water which seeps through the finished floor around the drain head back into the drain.
Sealing a pan drain for pressure testing can be particularly problematic because merely plugging the central aperture still leaves these smaller openings unplugged allowing the pressurized fluid to escape therethrough. What is needed is a test plug for a shower pan drain which can seal the drain at a point below the collar so that no openings are left unplugged.
In addition to pressure testing of the drainage system, the shower pan itself needs to be tested for leaks. In this test, the shower drain is plugged and the pan is filled with water. The water is allowed to stand in the pan, and the pan is checked for leaks. Ideally, the same shower drain test plug can be used for both pressure testing of the drainage system and leak testing of the shower pan.